[PATCH v4 1/7] perf evlist: Introduce aux perf evlist

From: Wang Nan
Date: Mon May 23 2016 - 22:33:33 EST


An auxiliary evlist is created by perf_evlist__new_aux() using an existing
evlist as it parent. An auxiliary evlist can have its own 'struct perf_mmap',
but can't have other data. User should use its parent instead when accessing
other data.

Auxiliary evlists are container of 'struct perf_mmap'. It is introduced to
allow its parent evlist map different events to separated mmap. Following
commit creates an auxiliary evlist for overwritable events, because
overwritable events need a readonly and backward ring buffer, which is
different from normal events.

To achieve this goal, this patch carefully changes 'evlist' to
'evlist->parent' in all functions in the path of 'perf_evlist__mmap_ex',
except 'evlist->mmap' related operations, to make sure all evlist
modifications (like pollfd and event id hash tables) goes to original
evlist.

A 'evlist->parent' pointer is added to 'struct perf_evlist' and points to
the evlist itself for normal evlists.

Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Cc: He Kuang <hekuang@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Cc: pi3orama@xxxxxxx
---
tools/perf/util/evlist.c | 31 +++++++++++++++++++++----------
tools/perf/util/evlist.h | 3 +++
2 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index e82ba90..55cea69 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -45,6 +45,7 @@ void perf_evlist__init(struct perf_evlist *evlist, struct cpu_map *cpus,
fdarray__init(&evlist->pollfd, 64);
evlist->workload.pid = -1;
evlist->backward = false;
+ evlist->parent = evlist;
}

struct perf_evlist *perf_evlist__new(void)
@@ -989,7 +990,7 @@ static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx,
{
struct perf_evsel *evsel;

- evlist__for_each(evlist, evsel) {
+ evlist__for_each(evlist->parent, evsel) {
int fd;

if (evsel->system_wide && thread)
@@ -1016,16 +1017,16 @@ static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx,
* Therefore don't add it for polling.
*/
if (!evsel->system_wide &&
- __perf_evlist__add_pollfd(evlist, fd, idx) < 0) {
+ __perf_evlist__add_pollfd(evlist->parent, fd, idx) < 0) {
perf_evlist__mmap_put(evlist, idx);
return -1;
}

if (evsel->attr.read_format & PERF_FORMAT_ID) {
- if (perf_evlist__id_add_fd(evlist, evsel, cpu, thread,
+ if (perf_evlist__id_add_fd(evlist->parent, evsel, cpu, thread,
fd) < 0)
return -1;
- perf_evlist__set_sid_idx(evlist, evsel, idx, cpu,
+ perf_evlist__set_sid_idx(evlist->parent, evsel, idx, cpu,
thread);
}
}
@@ -1066,13 +1067,13 @@ static int perf_evlist__mmap_per_thread(struct perf_evlist *evlist,
struct mmap_params *mp)
{
int thread;
- int nr_threads = thread_map__nr(evlist->threads);
+ int nr_threads = thread_map__nr(evlist->parent->threads);

pr_debug2("perf event ring buffer mmapped per thread\n");
for (thread = 0; thread < nr_threads; thread++) {
int output = -1;

- auxtrace_mmap_params__set_idx(&mp->auxtrace_mp, evlist, thread,
+ auxtrace_mmap_params__set_idx(&mp->auxtrace_mp, evlist->parent, thread,
false);

if (perf_evlist__mmap_per_evsel(evlist, thread, mp, 0, thread,
@@ -1211,8 +1212,8 @@ int perf_evlist__mmap_ex(struct perf_evlist *evlist, unsigned int pages,
bool auxtrace_overwrite)
{
struct perf_evsel *evsel;
- const struct cpu_map *cpus = evlist->cpus;
- const struct thread_map *threads = evlist->threads;
+ const struct cpu_map *cpus = evlist->parent->cpus;
+ const struct thread_map *threads = evlist->parent->threads;
struct mmap_params mp = {
.prot = PROT_READ | (overwrite ? 0 : PROT_WRITE),
};
@@ -1220,7 +1221,7 @@ int perf_evlist__mmap_ex(struct perf_evlist *evlist, unsigned int pages,
if (evlist->mmap == NULL && perf_evlist__alloc_mmap(evlist) < 0)
return -ENOMEM;

- if (evlist->pollfd.entries == NULL && perf_evlist__alloc_pollfd(evlist) < 0)
+ if (evlist->parent->pollfd.entries == NULL && perf_evlist__alloc_pollfd(evlist->parent) < 0)
return -ENOMEM;

evlist->overwrite = overwrite;
@@ -1231,7 +1232,7 @@ int perf_evlist__mmap_ex(struct perf_evlist *evlist, unsigned int pages,
auxtrace_mmap_params__init(&mp.auxtrace_mp, evlist->mmap_len,
auxtrace_pages, auxtrace_overwrite);

- evlist__for_each(evlist, evsel) {
+ evlist__for_each(evlist->parent, evsel) {
if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
evsel->sample_id == NULL &&
perf_evsel__alloc_id(evsel, cpu_map__nr(cpus), threads->nr) < 0)
@@ -1888,3 +1889,13 @@ perf_evlist__find_evsel_by_str(struct perf_evlist *evlist,

return NULL;
}
+
+struct perf_evlist *perf_evlist__new_aux(struct perf_evlist *parent)
+{
+ struct perf_evlist *evlist = zalloc(sizeof(*evlist));
+
+ if (evlist != NULL)
+ perf_evlist__init(evlist, parent->cpus, parent->threads);
+ evlist->parent = parent->parent;
+ return evlist;
+}
diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h
index d740fb8..0505012 100644
--- a/tools/perf/util/evlist.h
+++ b/tools/perf/util/evlist.h
@@ -60,6 +60,7 @@ struct perf_evlist {
struct perf_evsel *selected;
struct events_stats stats;
struct perf_env *env;
+ struct perf_evlist *parent;
};

struct perf_evsel_str_handler {
@@ -70,6 +71,8 @@ struct perf_evsel_str_handler {
struct perf_evlist *perf_evlist__new(void);
struct perf_evlist *perf_evlist__new_default(void);
struct perf_evlist *perf_evlist__new_dummy(void);
+struct perf_evlist *perf_evlist__new_aux(struct perf_evlist *);
+
void perf_evlist__init(struct perf_evlist *evlist, struct cpu_map *cpus,
struct thread_map *threads);
void perf_evlist__exit(struct perf_evlist *evlist);
--
1.8.3.4